Trehalose dehydration under confined conditions

A DSC study of the dehydration process of trehalose dihydrate (TREh) crystals has been carried out by tuning scanning rates of the product formation, under “controlled evaporation rates” (confined conditions). The rationale for this study is the construction of a dynamic diagram as a function of the time scale of trehalose transformations and the timescale of water effusion. Results at different rates of heating and of water evaporation indicate that only dehydration of TREh crystals and melting of the TREβ form are constantly present. Amorphous state can be thermally produced under different ways: (a) by direct amorphisation of TREh; (b) by passing through the TREα form; (c) by cooling the liquid formed after TREβ melting. The anhydrous TREα form is produced from TREh under gentle conditions of low scanning rates (large transformation times) and high evaporation rates (low humidity) even at relatively low temperatures (60 °C).